During his first full-throttle "persistence hunt," the South African biologist Louis Liebenberg was working with bushmen in the Kalahari Desert in the early 1990s. Armed with handmade bows and arrows, the hunters had been stalking kudu—a nimble antelope, slightly smaller than an elk. When a young stag split off from the herd, the bushmen ran flat-out after it.
The kudu moved quickly out of sight in the brushy Kalahari landscape. But keeping up was more than just a matter of running; the hunters also needed to pick up footprints in the sand on the fly. Liebenberg, then age 30, hadn't done the conditioning to be a long-distance runner, and he was wearing heavy leather boots as a precaution against poisonous snakes. And this was shaping up to be a hard run.